MS Access databases are designed to be single user work station applications. As a single user work station application they work well.

In a server environment experience shows that MS Access databases seem to cope reasonably well, but only with a relatively small amount of traffic. If the database receives more then a few concurrent hits it's performance will degrade.

In multi user applications, such as web sites, sites that attract any more then a minimum number of visitors should consider upgrading to the .NET/MS SQL platform.